One-chip multimodal sensors that can perform a variety of different biological functions are highly sought after and extremely valuable in the medical industry. Such sensors can provide a modular platform for: liquid biopsy including cell enrichment and cell characterization, such as electrical, optical and fluorescence; and sequencing of genomes including optical detection, charge detection and dual detection.
To carry out the sequencing of the human genome, the DNA (deoxyribonucleic acid) is cut into short fragments, the fragments are sequenced simultaneously and the data may then be assembled using sophisticated computer technology. DNA sequencing is the process of determining the precise order of nucleotides (thymine, adenine, guanine, and cytosine) within a DNA molecule. DNA sequencing by synthesis is commonly achieved using one of two sensor modalities to monitor nucleotide incorporation. The two sensed modes or modalities are optical detection of fluorescently tagged nucleotides and the use of ion selective field effect transistors (ISFETs) to detect hydrogen ions that are released when a nucleotide is incorporated onto a target DNA fragment.
Some lab-on-a-chip type devices that analyze cells and their genomic content have been proposed but have all been in silicon on silicon substrates. This raises at least two major problems. One is that these silicon devices are relatively expensive and in the medical field a device of this type is almost exclusively used only once and discarded. Multiple uses require extensive cleaning which is even more costly than discarding the chip. Further in many of the tests or sensing processes, a high voltage (in excess of 50 volts) is required and silicon devices cannot withstand this voltage.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide a new and improved metal oxide TFT-based sensor with multiple transistors and multiple sensing modalities.
It is another object of the present invention to provide a new and improved metal oxide TFT-based sensor with multiple transistors that is relatively inexpensive and easy to use.